Brick Selection Updates - fixes #1520 fixes #1829 fixes #1929

Some new Brick selecting features

* Bricks are now de-selectable
  * Click on the phone or on blank app space or on gray canvas area
* Editables section is blanked out when there is no visible selected component
* When you select a component on a page and come back to that page, the same element becomes selected

Let me know if you would like more detailed steps to test, or if this provides enough info.